Archimedes (c. 287–212 BC)

Oil painting of Archimedes by the Italian artist Domenico Fetti (1589-1624). It was painted about 1620 and measures 98 x 73.5 centimeters. It now resides in the Gemäldegalerie Alte Meister, in Dresden, Germany. This is just a fanciful representation. No true likeness of Aristotle survives.

Archimedes, born in Syracuse, the son of an astronomer, was one of the most prominent of Greek scientists and mathematicians.
He became a popular
figure because of his involvement in the defense of Syracuse against the
Roman siege in the first and second Punic Wars when his war machines helped
keep the Romans at bay (see Archimedes
and the burning mirrors). He also devised a scheme to move a full-size
ship, complete with crew and cargo, by pulling a single rope, invented the
irrigation device known as the Archimedean
screw, and, according to one of many legends about him, is said to have
discovered the principle of buoyancy while taking a bath and then ran into
the street naked shouting "eureka" ("I found it!").

In his book The Sand Reckoner he brought to wider attention the heliocentric theory of Aristarchus and played
an important role in demystifying the cosmos. To him goes the credit of
constructing the first known planetarium (based on the geocentric model), a fantastic
instrument of brass, powered by water, that was eventually shipped to Rome
and admired there by Cicero two centuries later.

Also in The Sand Reckoner, Archimedes described a positional number
system and used it to write the equivalent of numbers up to 8 ×
1064 – the number of grains of sand he thought it would
take to fill the universe. He devised a rule-of-thumb method to do private
calculations that closely resembles integral calculus (2,000 years early!),
but then switched to geometric proof for his results. He demonstrated that
the ratio of a circle's perimeter to its diameter is the same as the ratio
of the circle's area to the square of the radius. Although he didn't call
this ratio "pi," he showed how to work it out
to arbitrary accuracy and gave an approximation of it as "exceeding 3 in
less than 1/7 but more than 10/71." He was the first, and possibly the only,
Greek mathematician to introduce mechanical curves (those traced by a moving
point) as legitimate objects of study, and he used the Archimedean
spiral to square the circle. He proved that the area and volume of the sphere are in the same ratio to the area
and volume of a circumscribed straight cylinder, a result that pleased him
so much that he made it his epitaph.

Archimedes is probably the first mathematical physicist on record, and the
best before Galileo and Newton.
He invented the field of statics, enunciated the law of the lever, the law
of equilibrium of fluids, and the law of buoyancy, and was the first to
identify the concept of center of gravity. Has also, perhaps erroneously,
been credited with the invention of a square dissection puzzle known as the loculus of
Archimedes.

Many of his original works were lost when the library at Alexandria burned
down and they survive only in Latin or Arabic translations. Plutarch wrote
of him: "... being perpetually charmed by his familiar siren, that is, by
his geometry, he neglected to eat and drink and took no care of his person;
that he was often carried by force to the baths, and when there he would
trace geometrical figures in the ashes of the fire, and with his finger
draws lines upon his body when it was anointed with oil, being in a state
of great ecstasy and divinely possessed by his science."